The debate about US power and purpose glosses over the more important issue - that of leadership.

Any discussion of US foreign policy begins with an understanding and appreciation of American "power" and influence in an evolving and uncertain world. The conversation often starts with the assertion that the US is the "indispensable nation", as President Barack Obama insisted in the candidates' foreign policy debate. But the debate about US power and purpose glosses over the more important issue - that of leadership.

While considerable ink has been spilled over the first two items, precious little attention has been given to the third. In fact, the tendency is to conflate them and to assume that power is leadership. That sort of reasoning is lazy, wrong and dangerous. We need to explore the meaning of leadership on its own terms if a discussion of US power is to bear fruit.

This conversation has assumed greater importance in Asia as the US embraces foreign and security policies that put the region at the top of the list of US priorities; and as Asian officials and analysts witness the rise of China, and watch with no small amount of exasperation the spectacle of Washington Beltway politics. US interlocutors have done their best to quiet Asian concerns about US disengagement.

Sanity may well be just around the corner; after the election, US politicians will probably strike a deal that stabilises the US fiscal situation and provides reassurance that America's "rebalancing" towards Asia is not a hollow promise.

But a budget deal will address just one small element of a much larger issue: the nature of American power and leadership in the 21st century.

Let's be clear: by just about any measure, the US remains the most powerful nation on the planet. Its military remains superior by orders of magnitude to that of any competitor. For all the difficulties of the past few years, the US economy remains twice as large as China's and on a per capita basis China won't catch up for decades - if ever. The US remains the source of innovation and entrepreneurial energy and the destination of choice for students seeking a top-ranked education and the freedom to use that education to better themselves and the world.

And yet for all that power and influence, one vital fact remains: the US cannot dictate international outcomes. Americans (and others) may fancy ourselves a global policeman or the "indispensable power", but America's ability to construct solutions to foreign policy problems is much more limited. The US tends to emphasise strength, when the real issue is leadership. There is a simple way to differentiate between them: strength is the ability to blow things up; it takes leadership to build something in its place.

Unfortunately, the US has blurred the two concepts. That made some sense during the cold war, when hard power - strength - was the defining element of a world bifurcated into two competing camps. Today, international relations are much more complicated, with virtually all countries engaging in both co-operation and competition. In this environment, there is a premium on the ability to rally other countries - to cajole, convince or co-opt other governments to get on board. This demands another skill set.

Exercising leadership has always been difficult, but has become even more challenging with the return of Asia. The old world - the transatlantic order - rested on a common culture. While Asian nations have benefited from that order, they had little, if any, say in its creation. Not surprisingly, they now rightfully demand a seat at the table of international negotiations.

They represent a growing share of international wealth and they are expected to contribute more to resolving international issues. Often, those problems are found in their neighbourhood, meaning they have a stake in their resolution. The presumption that they will automatically endorse US solutions and actions is presumptuous.

Note that we said "Asians", not Chinese. Yes, China is now a major actor in Asia and globally. But Asia is more than China. Japan remains the world's third-largest economy. India is emerging. Indonesia, South Korea and others have earned a more prominent place - not only regionally but globally. They argue forcefully for a continued US presence and commitment to the region, but none wants to be told what to do or how to do it.

This is one of the least understood elements in US relations with Asia: while many, if not most, of these governments and publics want the US deeply engaged in their region, they want it on their terms. The US needs to engage those governments, understand their perspectives, and respect their prerogatives and priorities.

Topping that list of Asian concerns is the desire to avoid being forced to choose between the US and China. In truth, no one is asking them to. Every US pronouncement about its Asia policy includes a caveat that these policies are not aimed at China and that the region is big enough for both countries.

Indeed, it has been US policy, at least since Richard Nixon, not to contain or hold China back, but to help China rise. The US (and Japan, Europe and others) have invested billions in China in the belief that an interdependent China will be a force for peace and stability over the long run. Campaign chest-pounding aside, both Democratic and Republican administrations alike have seen the value in a policy of constructive engagement because it is in everyone's interest that Beijing ultimately be part of the solution to the region's problems rather than an underlying cause.

The US possesses the tools necessary to forge constructive, all-inclusive coalitions in Asia, but getting the desired results takes patience.

Doing the right thing is only half the battle. Doing it the right way also matters. That's leadership; that's real strength.